Climate and air quality impacts due to mitigation of non-methane near-term climate forcers

It is important to understand how future environmental policies will impact both climate change and air pollution. Although targeting near-term climate forcers (NTCFs), defined here as aerosols, tropospheric ozone, and precursor gases, should improve air quality, NTCF reductions will also impact cli...

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Main Authors: Allen, Robert J., Turnock, Steven, Nabat, Pierre, Neubauer, David, Lohmann, Ulrike, Olivié, Dirk, Oshima, Naga, Michou, Martine, Wu, Tongwen, Zhang, Jie, Takemura, Toshihiko, Schulz, Michael, Tsigaridis, Kostas, Bauer, Susanne E., Emmons, Louisa, Horowitz, Larry, Naik, Vaishali, Van Noije, Twan, Bergman, Tommi, Lamarque, Jean-François, Zanis, Prodromos, Tegen, Ina, Westervelt, Daniel M., Le Sager, Philippe, Good, Peter, Shim, Sungbo, O'Connor, Fiona, Akritidis, Dimitris, Georgoulias, Aristeidis K., Deushi, Makoto, Sentman, Lori T., John, Jasmin G., Fujimori, Shinichiro, Collins, William J.
Format: Text
Language:English
Published: ETH Zurich 2020
Subjects:
Online Access:https://dx.doi.org/10.3929/ethz-b-000438713
http://hdl.handle.net/20.500.11850/438713
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description It is important to understand how future environmental policies will impact both climate change and air pollution. Although targeting near-term climate forcers (NTCFs), defined here as aerosols, tropospheric ozone, and precursor gases, should improve air quality, NTCF reductions will also impact climate. Prior assessments of the impact of NTCF mitigation on air quality and climate have been limited. This is related to the idealized nature of some prior studies, simplified treatment of aerosols and chemically reactive gases, as well as a lack of a sufficiently large number of models to quantify model diversity and robust responses. Here, we quantify the 2015–2055 climate and air quality effects of non-methane NTCFs using nine state-of-the-art chemistry–climate model simulations conducted for the Aerosol and Chemistry Model Intercomparison Project (AerChemMIP). Simulations are driven by two future scenarios featuring similar increases in greenhouse gases (GHGs) but with “weak” (SSP3-7.0) versus “strong” (SSP3-7.0-lowNTCF) levels of air quality control measures. As SSP3-7.0 lacks climate policy and has the highest levels of NTCFs, our results (e.g., surface warming) represent an upper bound. Unsurprisingly, we find significant improvements in air quality under NTCF mitigation (strong versus weak air quality controls). Surface fine particulate matter (PM2.5) and ozone (O3) decrease by −2.2±0.32 µg m−3 and −4.6±0.88 ppb, respectively (changes quoted here are for the entire 2015–2055 time period; uncertainty represents the 95 % confidence interval), over global land surfaces, with larger reductions in some regions including south and southeast Asia. Non-methane NTCF mitigation, however, leads to additional climate change due to the removal of aerosol which causes a net warming effect, including global mean surface temperature and precipitation increases of 0.25±0.12 K and 0.03±0.012 mm d−1, respectively. Similarly, increases in extreme weather indices, including the hottest and wettest days, also occur. Regionally, the largest warming and wetting occurs over Asia, including central and north Asia (0.66±0.20 K and 0.03±0.02 mm d−1), south Asia (0.47±0.16 K and 0.17±0.09 mm d−1), and east Asia (0.46±0.20 K and 0.15±0.06 mm d−1). Relatively large warming and wetting of the Arctic also occur at 0.59±0.36 K and 0.04±0.02 mm d−1, respectively. Similar surface warming occurs in model simulations with aerosol-only mitigation, implying weak cooling due to ozone reductions. Our findings suggest that future policies that aggressively target non-methane NTCF reductions will improve air quality but will lead to additional surface warming, particularly in Asia and the Arctic. Policies that address other NTCFs including methane, as well as carbon dioxide emissions, must also be adopted to meet climate mitigation goals. : Atmospheric Chemistry and Physics, 20 (16) : ISSN:1680-7375 : ISSN:1680-7367
format Text
author Allen, Robert J.
Turnock, Steven
Nabat, Pierre
Neubauer, David
Lohmann, Ulrike
Olivié, Dirk
Oshima, Naga
Michou, Martine
Wu, Tongwen
Zhang, Jie
Takemura, Toshihiko
Schulz, Michael
Tsigaridis, Kostas
Bauer, Susanne E.
Emmons, Louisa
Horowitz, Larry
Naik, Vaishali
Van Noije, Twan
Bergman, Tommi
Lamarque, Jean-François
Zanis, Prodromos
Tegen, Ina
Westervelt, Daniel M.
Le Sager, Philippe
Good, Peter
Shim, Sungbo
O'Connor, Fiona
Akritidis, Dimitris
Georgoulias, Aristeidis K.
Deushi, Makoto
Sentman, Lori T.
John, Jasmin G.
Fujimori, Shinichiro
Collins, William J.
spellingShingle Allen, Robert J.
Turnock, Steven
Nabat, Pierre
Neubauer, David
Lohmann, Ulrike
Olivié, Dirk
Oshima, Naga
Michou, Martine
Wu, Tongwen
Zhang, Jie
Takemura, Toshihiko
Schulz, Michael
Tsigaridis, Kostas
Bauer, Susanne E.
Emmons, Louisa
Horowitz, Larry
Naik, Vaishali
Van Noije, Twan
Bergman, Tommi
Lamarque, Jean-François
Zanis, Prodromos
Tegen, Ina
Westervelt, Daniel M.
Le Sager, Philippe
Good, Peter
Shim, Sungbo
O'Connor, Fiona
Akritidis, Dimitris
Georgoulias, Aristeidis K.
Deushi, Makoto
Sentman, Lori T.
John, Jasmin G.
Fujimori, Shinichiro
Collins, William J.
Climate and air quality impacts due to mitigation of non-methane near-term climate forcers
author_facet Allen, Robert J.
Turnock, Steven
Nabat, Pierre
Neubauer, David
Lohmann, Ulrike
Olivié, Dirk
Oshima, Naga
Michou, Martine
Wu, Tongwen
Zhang, Jie
Takemura, Toshihiko
Schulz, Michael
Tsigaridis, Kostas
Bauer, Susanne E.
Emmons, Louisa
Horowitz, Larry
Naik, Vaishali
Van Noije, Twan
Bergman, Tommi
Lamarque, Jean-François
Zanis, Prodromos
Tegen, Ina
Westervelt, Daniel M.
Le Sager, Philippe
Good, Peter
Shim, Sungbo
O'Connor, Fiona
Akritidis, Dimitris
Georgoulias, Aristeidis K.
Deushi, Makoto
Sentman, Lori T.
John, Jasmin G.
Fujimori, Shinichiro
Collins, William J.
author_sort Allen, Robert J.
title Climate and air quality impacts due to mitigation of non-methane near-term climate forcers
title_short Climate and air quality impacts due to mitigation of non-methane near-term climate forcers
title_full Climate and air quality impacts due to mitigation of non-methane near-term climate forcers
title_fullStr Climate and air quality impacts due to mitigation of non-methane near-term climate forcers
title_full_unstemmed Climate and air quality impacts due to mitigation of non-methane near-term climate forcers
title_sort climate and air quality impacts due to mitigation of non-methane near-term climate forcers
publisher ETH Zurich
publishDate 2020
url https://dx.doi.org/10.3929/ethz-b-000438713
http://hdl.handle.net/20.500.11850/438713
geographic Arctic
geographic_facet Arctic
genre Arctic
Climate change
genre_facet Arctic
Climate change
op_rights info:eu-repo/semantics/openAccess
Creative Commons Attribution 4.0 International
https://creativecommons.org/licenses/by/4.0/legalcode
cc-by-4.0
op_rightsnorm CC-BY
op_doi https://doi.org/10.3929/ethz-b-000438713
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spelling ftdatacite:10.3929/ethz-b-000438713 2023-05-15T15:08:00+02:00 Climate and air quality impacts due to mitigation of non-methane near-term climate forcers Allen, Robert J. Turnock, Steven Nabat, Pierre Neubauer, David Lohmann, Ulrike Olivié, Dirk Oshima, Naga Michou, Martine Wu, Tongwen Zhang, Jie Takemura, Toshihiko Schulz, Michael Tsigaridis, Kostas Bauer, Susanne E. Emmons, Louisa Horowitz, Larry Naik, Vaishali Van Noije, Twan Bergman, Tommi Lamarque, Jean-François Zanis, Prodromos Tegen, Ina Westervelt, Daniel M. Le Sager, Philippe Good, Peter Shim, Sungbo O'Connor, Fiona Akritidis, Dimitris Georgoulias, Aristeidis K. Deushi, Makoto Sentman, Lori T. John, Jasmin G. Fujimori, Shinichiro Collins, William J. 2020 application/pdf https://dx.doi.org/10.3929/ethz-b-000438713 http://hdl.handle.net/20.500.11850/438713 en eng ETH Zurich info:eu-repo/semantics/openAccess Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode cc-by-4.0 CC-BY Text article-journal Journal Article ScholarlyArticle 2020 ftdatacite https://doi.org/10.3929/ethz-b-000438713 2021-11-05T12:55:41Z It is important to understand how future environmental policies will impact both climate change and air pollution. Although targeting near-term climate forcers (NTCFs), defined here as aerosols, tropospheric ozone, and precursor gases, should improve air quality, NTCF reductions will also impact climate. Prior assessments of the impact of NTCF mitigation on air quality and climate have been limited. This is related to the idealized nature of some prior studies, simplified treatment of aerosols and chemically reactive gases, as well as a lack of a sufficiently large number of models to quantify model diversity and robust responses. Here, we quantify the 2015–2055 climate and air quality effects of non-methane NTCFs using nine state-of-the-art chemistry–climate model simulations conducted for the Aerosol and Chemistry Model Intercomparison Project (AerChemMIP). Simulations are driven by two future scenarios featuring similar increases in greenhouse gases (GHGs) but with “weak” (SSP3-7.0) versus “strong” (SSP3-7.0-lowNTCF) levels of air quality control measures. As SSP3-7.0 lacks climate policy and has the highest levels of NTCFs, our results (e.g., surface warming) represent an upper bound. Unsurprisingly, we find significant improvements in air quality under NTCF mitigation (strong versus weak air quality controls). Surface fine particulate matter (PM2.5) and ozone (O3) decrease by −2.2±0.32 µg m−3 and −4.6±0.88 ppb, respectively (changes quoted here are for the entire 2015–2055 time period; uncertainty represents the 95 % confidence interval), over global land surfaces, with larger reductions in some regions including south and southeast Asia. Non-methane NTCF mitigation, however, leads to additional climate change due to the removal of aerosol which causes a net warming effect, including global mean surface temperature and precipitation increases of 0.25±0.12 K and 0.03±0.012 mm d−1, respectively. Similarly, increases in extreme weather indices, including the hottest and wettest days, also occur. Regionally, the largest warming and wetting occurs over Asia, including central and north Asia (0.66±0.20 K and 0.03±0.02 mm d−1), south Asia (0.47±0.16 K and 0.17±0.09 mm d−1), and east Asia (0.46±0.20 K and 0.15±0.06 mm d−1). Relatively large warming and wetting of the Arctic also occur at 0.59±0.36 K and 0.04±0.02 mm d−1, respectively. Similar surface warming occurs in model simulations with aerosol-only mitigation, implying weak cooling due to ozone reductions. Our findings suggest that future policies that aggressively target non-methane NTCF reductions will improve air quality but will lead to additional surface warming, particularly in Asia and the Arctic. Policies that address other NTCFs including methane, as well as carbon dioxide emissions, must also be adopted to meet climate mitigation goals. : Atmospheric Chemistry and Physics, 20 (16) : ISSN:1680-7375 : ISSN:1680-7367 Text Arctic Climate change DataCite Metadata Store (German National Library of Science and Technology) Arctic